Display panel capable of reducing mismatching rc effect during signal transmission and method of manufacturing the same

ABSTRACT

A display panel includes a substrate, a plurality of data lines, a driver integrated circuit, and a plurality of connecting lines. The data lines of the display panel are disposed on a display area of the substrate for signal transmission. The driver integrated circuit is electrically connected to the data lines for providing driving signals required for panel operations. Each data line of the display panel is electrically connected to the driver integrated circuit via a corresponding connecting line. A first connecting line of the connecting lines includes a first section and a second section, wherein a thickness of the second section is substantially thinner than that of the first section.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a display panel, and more particularly,to a display panel capable of reducing mismatching RC effect duringsignal transmission and method of manufacturing the same.

2. Description of the Prior Art

The progress of science and technology has led to small, effective, andportable intelligent information products becoming a part of our lives.Display devices play an important role because all intelligentinformation products, such as mobile phones, personal digital assistants(PDAs), or notebook computers, need display devices to be acommunication interface. Because the liquid crystal display (LCD) panelis characterized by light weight, low power consumption, and lowradiation, the LCD is a mature flat panel display technology. Due to thehigh vision quality requirements, the LCD is developed toward highquality, high resolution, and low price.

Please refer to FIG. 1, which is a schematic diagram of a prior art LCDpanel 10. A display area 20 of the LCD panel 10 comprises a plurality ofparallel data lines 12 and a plurality of parallel scanning lines 14.The data lines 12 are perpendicular to and interlaced with the scanninglines 14, and a pixel unit 16 is formed between each two adjacent datalines 12 and two adjacent scanning lines 14. The data lines 12 of theLCD panel 10 are separated into a plurality of groups of data lines.Each of the groups of data lines receives signals via a correspondingsource driver S₁-S_(m). The scanning lines 14 of the LCD panel 10 areseparated into a plurality of groups of scanning lines. Each of thegroups of the scanning lines receives signal via a corresponding gatedriver integrated circuit (IC) G₁-G_(n). The source drivers S₁-S_(m) andthe gate driver ICs G₁-G_(n) are positioned on a non-display area 30 ofthe LCD panel 10. In order to enhance the image quality of the LCDpanel, the number of the data lines of the LCD panel is usuallyincreased. In order to reduce the cost of the LCD panel, the number ofthe source drivers is usually decreased. Therefore, in order to enhancethe image quality of the LCD panel and to reduce the cost of the LCDpanel, the number of data lines connected to a single source drivershould be increased.

Please refer to FIG. 2, which is an enlarged view of the source driverS₁ of the LCD panel 10. There are a plurality of connecting pads 22 andconnecting wires C₁-C_(2m) connected between the source driver S₁ andthe data lines D₁-D_(2m). Therefore, the source driver S₁ iselectrically connected to the data lines D₁-D_(2m). The connecting wiresC₁-C_(2m) are linear wiring to connect with the source driver S₁ and theconnecting pads 22. As shown in FIG. 2, the lengths of the peripheryconnecting wires C₁ and C_(2m) are greater than the length of the middleconnecting wire C_(m). The greater the number of connecting wiresC₁-C_(2m), the greater the difference between the periphery connectingwire C₁ or C_(2m) and the middle connecting wire C_(m). Because theresistance of the connecting wire is directly proportional to itslength, the resistance of the periphery connecting wire C₁ or C_(2m) isgreater than the resistance of the middle connecting wire C_(m).Therefore, the impedance of the periphery connecting wire C₁ or C_(2m)while the source driver S₁ is outputting is greater than that of anyother connecting wire C₂-C_(2m−1). Due to the mismatching RC effectduring signal transmission, the image quality of the LCD panel 10 isworsened.

Please refer to FIG. 3, which is a schematic diagram of another priorart LCD panel 10′. In order to overcome the problem of mismatching RCeffect, the middle connecting wire C_(m) has zigzag wiring to increasethe resistance of the connecting wire C_(m) and to decrease thedifference between the RC effect of the connecting wire C_(m) and RCeffect of the periphery connecting wire C₁ or C_(2m). However, becausethe number of data lines D₁-D_(2m) electrically connected to the sourcedriver S₁ and the number of the connecting wires C₁-C_(2m) are large,the space for laying out the connecting wire C_(m) is limited.Therefore, even through the connecting wire C_(m) is zigzag wiring, thedifference between the length of the connecting wire C_(m) and theconnecting wire C₁ or C_(2m) cannot be decreased effectively so that thedifference between the RC effect of the connecting wire C_(m) and RCeffect of the connecting wire C₁ or C_(2m) is decreased slightly. Inaddition, the difference between the resistance of other connectingwires adjacent to the connecting wire C_(m), such as C_(m−2), C_(m−1),C_(m+1) or C_(m+2), and the periphery connecting wire C₁ or C_(2m)cannot be ignored. Because of the limited layout area, the connectingwire C_(m−2), C_(m−1), C_(m+1) or C_(m+2) is difficult to be made tozigzag when the connecting wire C_(m) is made to zigzag. In summary, theRC effect of the data lines and the connecting wire of the LCD panel 10′cannot be reduced effectively, so the image quality of the LCD panel 10′cannot be improved.

SUMMARY OF THE INVENTION

According to the claimed invention, a display panel is disclosed. Thedisplay panel comprises a substrate having a display area, a pluralityof wires positioned over the display area of the substrate for signaltransmission, a driver integrated circuit electrically connected to thewires for providing driving signals required for operations of thedisplay panel, and a plurality of connecting wires of which each iselectrically connected to a corresponding one of the wires and thedriver integrated circuit. A first connecting wire of the connectingwires includes a first section and a second section, and a thickness ofthe second section is substantially different from that of the firstsection.

The present invention also discloses a method to manufacture a displaypanel. The method comprises setting up a plurality of wires for signaltransmission over a display area of a substrate of the display panel,setting up a driver integrated circuit for providing driving signalsrequired for operations of the display panel, and forming a firstconnecting wire for connecting one of the wires to the driver integratedcircuit. The first connecting wire includes a first section and a secondsection, and a thickness of the second section is substantially thinnerthan that of the first section.

These and other objectives of the present invention will no doubt becomeobvious to those of ordinary skill in the art after reading thefollowing detailed description of the preferred embodiment that isillustrated in the various figures and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of a prior art LCD panel.

FIG. 2 is an enlarged view of the source driver of the LCD panel shownin FIG. 1.

FIG. 3 is a schematic diagram of another prior art LCD panel.

FIG. 4 illustrates the layout of a driver circuit and wires of a firstembodiment LCD panel according to the present invention.

FIG. 5 is a cross-sectional diagram of the middle connecting wire of thefirst embodiment LCD panel.

FIG. 6 illustrates the layout of a driver circuit and wires of a secondembodiment LCD panel according to the present invention.

FIG. 7 illustrates the layout of a driver circuit and wires of a thirdembodiment LCD panel according to the present invention.

DETAILED DESCRIPTION

Please refer to FIG. 4, which illustrates the layout of a driver circuitand wires of a first embodiment LCD panel 40 according to the presentinvention. In the embodiment, the source driver IC S₁ and the data linesD₁-D_(2m) of the LCD panel 40 are used to explain how to perform alayout according to the present invention. Supposing that the sourcedriver IC S₁ transmits signals to the data lines D₁-D_(2m), it isnecessary to set up a plurality of connecting pads 42 and a plurality ofconnecting wires L₁-L_(2m) on the LCD panel 40 to electrically connectthe data lines D₁-D_(2m) to the source driver IC S₁. In the firstembodiment, the connecting wires L₁-L_(2m) are linear wiring to connectthe connecting pads 42 to the source driver circuit S₁. The resistance Rof the connecting wire L₁-L_(2m) can be described by:R=σL/A

wherein σ is a coefficient of resistance of the connecting wiresL₁-L_(2m), L is a length of the connecting wires L₁-L_(2m), and A is across-sectional area of the connecting wires L₁-L_(2m).

Because the lengths of the periphery connecting wires L₁ and L_(2m) aregreater than the length of the middle connecting wire L_(m) and theresistances of the connecting wires L₁-L_(2m) is directly proportionalto their lengths, a halftone mask is used to form the connecting wiresL₁-L_(2m) to reduce thickness of some sections of the connecting wiresL₁-L_(2m) to reduce the differences of the resistances of the connectingwires L₁-L_(2m). In the first embodiment, some material of the sectionsB₁-B_(t) of the shortest connecting wire L_(m) is removed by executingan exposure procedure using the halftone mask to thin the sectionsB₁-B_(t) of the connecting wire L_(m). Therefore, the cross-sectionalareas of the sections B₁-B_(t) are less than that of the connecting wireL_(m), where the B₁-B_(t) are indicated by dotted lines in FIG. 4.Because resistance of a connecting wire is inversely proportional to thecross-sectional area of the connecting wire, the difference between theresistance of the connecting wire L_(m) and the resistance of theperipheral connecting wire L₁ or L_(2m) can be reduced by thinning thesections B₁-B_(t) of the connecting wire L_(m). In addition, the numberand the lengths of the sections B₁-B_(t) are determined according to thedifference between the resistance of the connecting wire L_(m) and theresistance of the peripheral connecting wire L₁ or L_(2m).

Please refer to FIG. 5, which is a cross-sectional diagram of theconnecting wire L_(m) of the first embodiment LCD panel 40. It indicatesthat the sections B₁-B_(t) of the connecting wire L_(m) are thinned.Therefore, the resistance of the sections B₁-B_(t) is greater than theresistance of other sections of the connecting wire L_(m), and thedifference between the resistance of the connecting wire L_(m) and theresistance of the peripheral connecting wire L₁ or L_(2m) is reduced.

In the first embodiment, only some sections of the connecting wire L_(m)are thinned. However, in a second embodiment of the present invention,the resistances of some connecting wires are increased by thinning theirsections. Please refer to FIG. 6, which illustrates the layout of adriver circuit and wires of a second embodiment LCD panel 60 accordingto the present invention. In the second embodiment, the source driver ICS₁ and the data lines D₁-D_(2m) of the LCD panel 60 are also used toexplain how to perform the layout according to the present invention. Inthe embodiment, with the exception of the longest connecting wires L₁and L_(2m), all connecting wires L₂-L_(2m−1) include some thinnedsections. The number and the lengths of the thinned sections of theconnecting wires L₂-L_(2m−1) are determined according to the differencesbetween the resistances of the connecting wires L₂-L_(2m−1) and theresistance of the peripheral connecting wire L₁ or L_(2m). Therefore,N(L_(m))>N(L_(m−1) or L_(m+1))>N(L_(m−2) or L_(m+2))> . . . >N(L₂ orL_(2m−1)), where N(L_(m)) represents the number of thinned sections ofthe connecting wire L_(m), and N(L_(p) or L_(q)) represents the numberof thinned sections of the connecting wire L_(p) or L_(q).

Please refer to FIG. 7, which illustrates the layout of a driver circuitand wires of a third embodiment LCD panel 70 according to the presentinvention. In the second embodiment, the source driver IC S₁ and thedata lines D₁-D_(2m) of the LCD panel 60 are used to explain how toperform the layout according to the present invention. In the thirdembodiment, the middle connecting wire L_(m) not only includes thethinned sections B₁-B_(t), but also is a zigzag-shaped wiring. Theresistance of the connecting wire L_(m), hence, is increased by thinningthe sections B₁-B_(t) and by elongating the connecting wire L_(m).Therefore, the difference between the resistance of the connecting wireL_(m) and the resistance of the peripheral connecting wire L₁ or L_(2m)can be reduced more effectively when the number of connecting wiresL₁-L_(2m) is large.

Even though the source driver IC S₁ and the data lines D₁-D_(2m) of theLCD panels 40, 60, and 70 are used to describe how to perform the layoutaccording to the present invention, it should be noted that the presentinvention also can be adopted to wiring between the scanning lines andthe gate driver ICs of the LCD panels. The number of the connectingwires, the number and the lengths of the thinned sections, and thenumber of the connecting wires including the thinned sections are notlimited by the above embodiments. In addition, the source driver ICs andthe gate driver ICs can be positioned on a non-display area of thesubstrate of the LCD panel or be positioned adjacent to the substratevia a flexible printed circuit (FPC) board.

In contrast with the prior art LCD panel, the mismatching RC effectduring signal transmission of the LCD panels 40, 60, and 70 of thepresent invention is reduced by executing an exposure procedure using ahalftone mask to thin some sections of longer connecting wire connectedto driver ICs. Therefore, the connecting wires can be wired within alimited layout area so that the number of connecting wires coupled toeach driver IC is increased. The image quality of the LCD panels can beimproved effectively. Moreover, the resolution of LCD panels can beincreased, and the cost of LCD panels can be reduced.

Those skilled in the art will readily observe that numerousmodifications and alterations of the device and method may be made whileretaining the teachings of the invention. Accordingly, the abovedisclosure should be construed as limited only by the metes and boundsof the appended claims.

1. A display panel comprising: a substrate having a display area; aplurality of wires positioned over the display area of the substrate forsignal transmission; a driver integrated circuit electrically connectedto the wires for providing driving signals required for operations ofthe display panel; and a plurality of connecting wires of which each iselectrically connected to a corresponding one of the wires and thedriver integrated circuit, a first connecting wire of the connectingwires includes a first section and a second section, wherein a thicknessof the second section is substantially different from that of the firstsection.
 2. The display panel of claim 1 wherein the wires include aplurality of parallel scanning lines and a plurality parallel datalines, the scanning lines being perpendicular to and interlaced with thedata lines, a pixel unit being formed between each two adjacent scanninglines and two adjacent data lines.
 3. The display panel of claim 1wherein the wires are a plurality of parallel data lines, the driverintegrated circuit is a source driver integrated circuit, and connectingwires are electrically connected to the data lines and the source driverintegrated circuit.
 4. The display panel of claim 1 wherein the wiresare a plurality of parallel scanning lines, the driver integratedcircuit is a gate driver integrated circuit, and the connecting wiresare electrically connected to the scanning lines and the gate driverintegrated circuit.
 5. The display panel of claim 1 wherein values ofthicknesses of all sections of a second connecting wire of theconnecting wires are substantially equal.
 6. The display panel of claim5 wherein a length of the first connecting wire is less than a length ofthe second connecting wire.
 7. The display panel of claim 1 wherein allof the connecting wires are linear wiring.
 8. The display panel of claim1 wherein the first connecting wire is zigzagged wiring.
 9. The displaypanel of claim 1 being a liquid crystal display panel.
 10. The displaypanel of claim 1 wherein the substrate further comprises a non-displayarea, and the driver integrated circuit is positioned on the non-displayarea.
 11. The display panel of claim 1 further comprising a flexibleprinted circuit board, wherein the driver integrated circuit ispositioned adjacent to the substrate via the FPC board.
 12. A method formanufacturing a display panel, the method comprising: setting up aplurality of wires for signal transmission over a display area of asubstrate of the display panel; setting up a driver integrated circuitfor providing driving signals required for operations of the displaypanel; and forming a first connecting wire for connecting one of thewires to the driver integrated circuit, wherein the first connectingwire includes a first section and a second section, and a thickness ofthe second section is substantially thinner than that of the firstsection.
 13. The method of claim 12 wherein the first connecting wire isformed via a halftone mask.
 14. The method of claim 12 furthercomprising: forming a second connecting wire for connecting one of thewires to the driver integrated circuit, wherein the thicknesses of allsections of a second connecting wire are substantially equal.
 15. Themethod of claim 12 wherein setting up a driver integrated circuit forproviding driving signals required for operations of the display panelis setting up a driver integrated circuit on a non-display area of thesubstrate to provide driving signals required for operations of thedisplay panel.
 16. The method of claim 12 wherein setting up a driverintegrated circuit for providing driving signals required for operationsof the display panel is setting up a driver integrated circuit adjacentto the substrate to provide driving signals required for operations ofthe display panel.